Extreme obesity is affecting more children in the United States than ever before, according to a new study.

The study has suggested that the number of extremely obese children in the United States has risen steeply. It also revealed that extreme obesity can seriously cut short their lives by decades, than the normal-weight children.

The study, carried out by healthcare provider Kaiser Permanente, included more than 700,000 children and teenagers from Southern California, aged between 2 and 19.

The results of the study revealed that more than 7% of boys and 5% of girls fell in the "extremely obese" category. The study also found that extreme obesity hit its peak in boys at age 10. Among girls, obesity peaks twice, at age
12 and 18.

Corinna Koebnick, a researcher at Kaiser Permanente's Department of Research and Evaluation, and the lead author of the study, said, "Without major lifestyle changes, these kids face a 10 to 20 years shorter lifespan and will develop health problems in their 20s that we typically see in 40- to 60-year-olds".

Citing examples to explain her finding, Koebnick said, "Children who are extremely obese are at higher risk for heart disease, type 2 diabetes, fatty liver disease and joint problems, just to name a few".

The details of the study can be found in the Journal of Pediatrics.